See above paragraphs.
The irons are stiff. They seem to be solid and I would guess they are 17-4 or 431 steel. No complaints about the irons, they perform well when I hit them correctly. I also like the simple mallet putter that came with the set and the 56* sand wedge has become indispensable to my game.
About 3 months after purchase, I hit my best drive with the 460cc driver that came with the set, but the next drive was the worst slice I've ever hit. I turned the club over and noticed a sizable dent on the face of the club. Also, the impact had created a dent on the top of the club. Upon closer inspection, I noticed the face and body were cheaply put together and the division between face and body at the crown of the driver was starting to disintegrate. Now, I inspect my clubs prior to each round (clean out the grooves, wipe them down, etc.), so I know the driver was in at least good shape before the round. So far, I have been unable to find a way to contact Alien Golf to alert them to the issue. My swing speed is not very fast and I have not abused the club in any way.
A good bargain basement starter set that came with a bag, putter, 2 hybrids (replacing 3-4 irons), 5-SW, a Driver, and a 3 Wood. Just don't expect the driver to last very long.